An aircraft may include an electrical power distribution system for distributing power to various electrical subsystems at different voltage levels. For example, electrically-powered mechanical systems within the aircraft may use alternating current (AC) at relatively high voltage. In contrast, avionics systems typically operate using direct current (DC) at relatively low voltage. Electrical power may be created by generators that are driven by main engines of the aircraft. The electrical power created by the generators may be converted using equipment such as transformers, power electronics converters, or a combination of both, and is sent to various subsystems within the aircraft. The electrical power distribution system also includes a back-up power source, such as a battery, that is independent of the aircraft's main engine.
The conversion equipment may be located within a single, centralized location within the aircraft. In particular, the conversion equipment is typically located within the electronics equipment (EE) bay of the aircraft. The electrical power distribution system may transmit appropriate voltages from the conversion equipment located within the EE bay to various loads throughout the aircraft using multiple feeders. Specifically, the electrical power system may either have each load receive an individual feeder from the EE bay, or multiple loads may be ganged nearby the load and power is provided by a single large feeder. Each feeder requires wire protection. Wire protection may be accomplished using a circuit breaker, a solid-state power controller (SSPC), or a combined electronic control circuit and contactor sometimes referred to as an electrical load control unit (ELCU). Larger feeders may require larger protection devices, since higher fault currents are produced. However, this results in significant weight that is added to the aircraft.
Relatively thick wiring is typically used for the feeders between the conversion equipment in the EE bay and the loads. However, thicker feeder wires require a greater amount of insulation, which also adds weight to the aircraft. Moreover, lightning threats to the aircraft may increase as well due to the lower impedance that is created with thicker feeder wires. These lightning threats may become especially problematic for a composite based aircraft. This is because composite based aircraft are constructed of carbon fiber reinforced plastic (CFRP) that has limited shielding and current return capacity. Additionally, wire protection requirements will also increase due to the higher fault currents. Finally, routing multiple feeder wires from the EE bay, which is typically located at the front of the aircraft, throughout the entire length of the aircraft may result in a significant amount of wire being used. Longer feeder wires also add significant weight to the aircraft as well. Thus, there exists a continuing need for an improved, lighter electrical power distribution system in an aircraft.